Magnetron sputtering apparatus

Abstract

A magnetic assembly ( 15 ) is mounted on a lead screw ( 12 ) on one side of a spunter target ( 14 ). A further lead screw ( 11 ) carries a counter weight ( 16 ). The lead screws can be rotated by a stepper motor ( 13 ) to adjust the lateral positions of assembly ( 15 ) and weight ( 16 ). The stepper motor and hence the assembly ( 15 ), can be rotated about a vertical axis by shaft ( 17 ) and motor ( 18 ) so that a magnetic field can be swept around the target ( 14 ). The position of the assembly ( 15 ) is varied in accordance with a process characteristic.

1 . Sputtering apparatus including a target, a power source for the target and a magnetron disposed adjacent the target, including at least one magnet assembly movable laterally and rotationally relative to the target characterised in that the apparatus further includes control apparatus for varying the lateral position of an operational magnet of the assembly over the life of the target in accordance with a process characteristic.  
     
     
         2 . Sputtering apparatus as claimed in  claim 1  wherein the process characteristic is the accumulated power supplied to the target.  
     
     
         3 . Sputtering apparatus as claimed in  claim 1  wherein the vertical position of the magnet is also variable in accordance with a second process characteristic.  
     
     
         4 . Sputtering apparatus as claimed in  claim 3  wherein the second process characteristic is the target voltage.  
     
     
         5 . Sputtering apparatus as claimed in any one of the previous claims further comprising a magnet assembly position detector for providing a position signal to the control apparatus.  
     
     
         6 . Sputtering apparatus as claimed in  claim 5  wherein the position detector includes a reflector on the magnet assembly and a laser system for shining a light on the reflector and for detecting the hence reflected light.  
     
     
         7 . Sputtering apparatus as claimed in  claim 5  wherein the position detector is a linear encoder.  
     
     
         8 . Sputtering apparatus as claimed in any one of the preceding claims wherein the magnet assembly is mounted on a worm gear or lead screw extending generally parallel to the target and the apparatus further includes a stepper motor for rotating the gear or screw to move the magnet laterally.  
     
     
         9 . Sputtering apparatus further including a counter balance weight mounted on a lead screw.  
     
     
         10 . Sputtering apparatus as claimed in  claim 9  wherein the weight is moved more quickly than the magnetic assembly.  
     
     
         11 . Sputtering apparatus as claimed in any one of  claims 8  to  10  wherein the apparatus further includes a motor for rotating the worm gear or lead screw about an axis orthogonal to its axis.  
     
     
         12 . Sputtering apparatus as claimed in any one of  claims 1  to  4  wherein the magnet assembly is an array of electromagnets and the varying of the lateral position of the magnet is achieved by varying the power supplied to the assembly to activate one or more electromagnets within the array.  
     
     
         13 . Sputtering apparatus as claimed in any one of the preceding claims wherein the magnetron is an unbalanced magnetron.  
     
     
         14 . Sputtering apparatus as claimed in  claim 13  wherein the magnetron is unbalanced by magnets or an electromagnet encircling the region of the target.  
     
     
         15 . Sputtering apparatus as claimed in any one of the preceding claims wherein the process condition is the depth of material deposited at the base of a recess per unit time.  
     
     
         16 . A method of controlling a magnetron assembly having a magnet assembly laterally or vertically and laterally movable with respect to a target characterised in that the method includes monitoring a process characteristic and adjusting the position of an operational magnet of the assembly in accordance with that characteristic.  
     
     
         17 . A method as claimed in  claim 16  wherein the characteristic is monitored remotely.  
     
     
         18 . A method as claimed in  claim 16  or  claim 17  wherein the magnet assembly is an array of electromagnets and the movement is achieved by selection of the electromagnets in the array which are to be activated.  
     
     
         19 . A method as claimed in any one of  claims 16  to  18  wherein the process characteristic is the accumulated power supplied to the target and/or the depth of material deposited at the base of a recess per unit time.  
     
     
         20 . A method as claimed in any one of  claims 16  to  19  wherein the magnetron assembly operates in an unbalanced mode.  
     
     
         21 . A method as claimed in  claim 20  wherein a selection is made between balanced and unbalanced modes of the magnetron.